• Trenfield, Melanie
• Gissi, Francesca
• Jolley, Dianne
• Binet, Monique
• Van Dam, Joost

Abstract

Approximately 70% of the world’s nickel reserves are found in the tropics and mining in these regions contributes 40% to the global supply. As such, the associated mining and processing of nickel poses potential environmental risks to tropical marine ecosystems in close proximity to these mines. However, there is currently limited information on how mining activities in tropical regions could impact aquatic ecosystems. In the tropics there are many valuable and unique ecosystems, rich in biodiversity. To ensure their protection into the future it is important to develop and apply robust risk assessment tools. Water quality guidelines are a management tool which can be used by government and industry to set a threshold level for contaminants in aquatic systems.Due to the lack of ecotoxicity data for tropical marine species, there is currently no available water quality guideline for nickel specific to tropical species.In this study we investigated the toxicity of nickel to three tropical marine invertebrates, the gastropod Nassarius dorsatus, barnacle Amphibalanus amphitrite, and copepod Acartia sinjiensis.All toxicity tests utilised chronic endpoints namely larval growth, metamorphosis (transition from nauplii to cyprid larvae) and larval development for the snail, barnacle and copepod respectively. Toxicity tests were carried out under environmentally relevant conditions (i.e. 27-30ᵒC, salinity 34-36‰, pH 8.1-8.4). Copper was also tested for quality assurance purposes and to allow for comparisons with previous studies. The copepod was the most sensitive species to nickel, with development inhibited by 10% (EC10) at 5.5 (5.0-6.0) µg Ni/L (95% confidence limits (CL). Based on EC10 values, the gastropod and barnacle showed similar sensitivities to nickel with growth and metamorphosis inhibited by 10% at 64 (37-91) µg Ni/L and 67 (53-80) µg Ni/L, respectively. Based on existing data available in the literature, the copepod A. sinjiensis is the most sensitive tropical marine species to nickel reported so far. This study has provided high quality data which will contribute to the development of a water quality guideline for nickel in tropical marine waters. A species sensitivity distribution for the biological effects of Ni in tropical marine environments was created from the data generated in this paper and from available chronic toxicity data in the open literature; from a total of 12 species representing 6 different taxonomic groups, a 5% hazard concentration (HC5) could be determined at 8.7 µg/L Ni.

Topics

• impedance spectroscopy
• nickel
• copper
• toxicity